Remove distinct from enterprise.ready_for_checkout scope

Adapt use of enterprise scope not_ready_for_checkout to rails 4 by adding enterprises table alias to selected field id

app/controllers/spree/admin/base_controller_decorator.rb

@@ -52,7 +52,7 @@ Spree::Admin::BaseController.class_eval do
   def active_distributors_not_ready_for_checkout
     ocs = OrderCycle.managed_by(spree_current_user).active
     distributors = ocs.map(&:distributors).flatten.uniq
-    Enterprise.where('id IN (?)', distributors).not_ready_for_checkout
+    Enterprise.where('enterprises.id IN (?)', distributors).not_ready_for_checkout
   end
 
   def active_distributors_not_ready_for_checkout_message(distributors)

app/models/enterprise.rb

@@ -111,14 +111,14 @@ class Enterprise < ActiveRecord::Base
     joins(:shipping_methods).
       joins(:payment_methods).
       merge(Spree::PaymentMethod.available).
-      select('DISTINCT enterprises.id')
+      select('enterprises.id')
   }
   scope :not_ready_for_checkout, lambda {
     # When ready_for_checkout is empty, return all rows when there are no enterprises ready for
     # checkout.
     ready_enterprises = Enterprise.ready_for_checkout
     if ready_enterprises.present?
-      where("id NOT IN (?)", ready_enterprises)
+      where("enterprises.id NOT IN (?)", ready_enterprises)
     else
       where("TRUE")
     end